Anergy in tuberculosis.

Anergy in tuberculosis is of considerable clinical and immunological interest. Although negative skin reactions may be secondary to improper tuberculin testing or to certain diseases, drugs, vaccinations and constitutional factors known to affect cell-mediated immunity, often no underlying explanation is apparent. Unexplained negative reactions occur with a highly variable frequency in a wide variety of tuberculous infections. Anergy in tuberculosis is usually generalized, is often accompanied by other immunologic abnormalities, and frequently disappears as the disease is treated. Most anergic patients do not differ substantially from reactive patients in clinical features or prognosis. The mechanism of anergy in tuberculosis is unknown, but leading hypotheses suggest that immunologic compartmentalization, suppressor cells, or serum inhibitors (perhaps of mycobacterial origin) may be involved.